In the report’s most positive case, Britain would negotiate a
trade deal with the EU similar to Switzerland’s.

Under such a deal, the UK’s GDP per head would be £157 lower than
if Britain stayed in the EU.

In its most negative scenario, Britain would lose all trade
privileges arising from EU membership and its free trade
agreements.

Losses could run up to £3,471 per head in such a case, which
factors in trade isolation and the dent to innovation in the UK
and London’s position as a financial center.

“A Brexit is a losing game for everyone in Europe from an
economic perspective alone – particularly for the UK,” said
Aart De Geus, chairman and chief executive of the Bertelsmann
Stiftung.

“But aside from the economic consequences, it would be an
especially bitter setback for European integration as well as
Europe’s role in the world. Setting the course for a Brexit in
the House of Commons elections would weaken the EU.”

Europe’s economic powerhouse Germany would also suffer in the
event of a British exit.

The report calculates Germany could see GDP per capita losses
ranging from €30 (£21) to €700 (£500).